Organic Light-Emitting Diode (OLED) displays have become a hot spot for flat panel display research. Compared with a Liquid Crystal Display (LCD), an OLED display has lower power consumption, a lower production cost, a wider viewing angle, a faster response speed, and is self-luminous. Among existing technologies, OLED displays have come to replace traditional LCDs in flat panel displays in mobile phones, personal digital assistant devices (PDAs) and digital cameras.
An OLED display controls light emission of pixels using a light-emitting control signal. For example, when the light-emitting control signal is at a low level, the pixels emit light, and when the light-emitting control signal is at a high level, the pixels do not emit light. It is most common to adjust a ratio of the high level of the light-emitting control signal to its low level in order to control the brightness of the display, as illustrated by FIG. 1, which is a light-emitting timing diagram corresponding to a conventional display. Within one frame, the longer the light-emitting control signals (Emit(1) to Emit(N)) stay at the low level, the higher the brightness of the display will be; and the shorter the light-emitting control signals stay at the low level, the lower the brightness of the display is. Within one frame, in order to avoid display problems resulting from pixels being bright or dark for too long, usually several pulse cycles are designed in a light-emitting control signal. In each pulse cycle, the low level represents that a corresponding row of pixels are lightened, and the high level represents that a corresponding row of pixels do not emit light. So a higher duty cycle of the low level in the light-emitting control signal leads to a longer emission of light from pixels, and accordingly a higher brightness of the display.
With the existing brightness control method, when the brightness mode is fixed, each row of pixels receive a same light-emitting control signal for a long time, that is, all the controlled pixels become bright or dark periodically and regularly. However, due to response time from hysteresis of human eyes, rolling or static bright and dark bands might be seen on the screen of the display panel, which is not desired.